Chemical and Engineering Approaches for Soft Material Additive Manufacturing

Our research team focuses on discovering and developing new chemical approaches and engineering techniques for additive manufacturing. We place emphasis on: 1) incorporation of functional materials, particularly those that respond via conversion of mechanical force into chemical reactivity; 2) expansion of the materials space available for AM; 3) selective multi-material printing from “all-in-one” mixed-resin vats; and 4) unique methods for energy transduction that are atypical in additive manufacturing. As representative examples, we will discuss two unique approaches for additive manufacturing with silicone resins. In each example, we aim for complete geometric freedom as one would enjoy from vat photopolymerization or material fusion techniques, yet neither of our approaches use any photochemical or powder bed technologies. In one discovery, we realized that heating at a patterned photothermal interface (HAPPI) additive manufacturing could be achieved using near-IR light sources in combination with photothermal vat materials. In this way, we were able to construct 3D objects using patterned light while relying on thermal curing of traditional silicone resins. The preliminary mechanical properties of printed parts after thermal post-treatment are on par with those of molded parts. Separately, we discovered that high-intensity focused ultrasound can be used as a method for converting liquid silicone resins into cured 3D object, even through optically opaque barriers.